Elastomeric railroad crosstie

ABSTRACT

A plurality of elongated, substantially planar, elastomeric members are assembled together in a stack such that the members are generally aligned with each other. The members are made of a stack of tire treads. A means of binding is provided for holding the stack of members together and maintaining their alignment. The addition of one or more rigid longitudinal element(s) provides stiffness.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to railroad crossties.

[0003] 2. Description of the Related Art

[0004] Conventional treated wooden railroad crossties eventually rot andmust be disposed of and replaced. It is estimated that the average lifeof a wooden railroad tie is only fifteen years. Concrete crossties, amore recent innovation, have a history of breaking. Rotted and brokencrossties can lead to train derailments. What is needed is aninexpensive, long-lasting railroad crosstie which neither rots norbreaks.

[0005] Most railroad crossties used in this country today are lumberbeams, approximately seven inches thick by nine inches wide by eight anda half feet long, which have been cut from sections of tree trunksselected to be free from decay, worm holes, and other imperfections.Before being placed into service as crossties, these beams are treatedwith chemicals to protect them against exposure to weather, insects, andmicrobes.

[0006] The treatment used on the wood crossties can be creosote, an oilyliquid preservative, or chromated copper arsenic, or other chemicals.When rain, snow, and other weather elements impact on crossties whichhave been placed in a stone ballast roadbed, these chemicals migrateinto the surrounding soil, producing a harmful environmental effect.

[0007] The sun has an evaporative effect on the chemical treatment ofthe wood crossties. As this evaporation of the chemical preservativescontinues, the cellulose wood fibers become exposed, and this leads tothe degradation of the wood crossties.

[0008] When taken out of service due to disintegration, the disposal oftreated wood crossties causes another environmental problem. Many of thestate Environmental Protection Agencies do not allow creosoted woodcrossties to be burned or incinerated because of the emission of toxicfumes. The acid-treated wood ties can be granulated and buried, howeverthis also pollutes the soil. Some ties are sold for landscaping orburned as fuel in specialized furnaces, but many must be buriedunderground, as some state and local laws prohibit their being burned inthe open or being left along the railroad right-of-way for extendedperiods of time.

[0009] The normal service life of a wooden crosstie is about thirteenyears. There are many crossties, however, that are in service wellbeyond this time period. These older ties are generally splitting androtting, and cannot hold a cut spike (fastener). These older ties areleaching harmful chemicals into the soil, and potentially causingderailments.

[0010] Because wood crossties have a very limited useful lifespan, theymust be replaced regularly. The U.S. railroad industry replacesapproximately 15 million lumber crossties annually. New lumber crosstiesmust be purchased and treated, transported to the rail lines, anddistributed along the railbeds. They then must be installed usingcomplex machinery and much skilled labor. During this process, theaffected rail lines are shut down for days at a time. The cost to theindustry, in terms of materials, labor, and disruption of rail service,is enormous.

[0011] Thus the major disadvantages of using lumber beams for railroadcrossties are the ever-increasing cost of raw lumber, the difficulty ofapplying creosote or other preservatives with sufficient penetration toprevent rapid deterioration, the negative environmental impact of thechemicals used to treat wood crossties, and the expense of continuallyreplacing crossties that are split or rotten.

[0012] Previous attempts have been made to develop a substitute for theconventional wood crosstie. One such attempt, as shown in Groff U.S.Pat. No. 3,289,940, involved manufacturing ties from synthetic resins.Other attempts include ties made from steel, concrete, or thinparticleboard sheets made from recycled wood crossties or otherlignocellulosic materials and laminated together (see U.S. patentreferences cited). These attempts have not been successful in replacingwood ties on a large scale, due to several factors, including highercost, lack of sufficient strength and durability to withstand thecyclical bending loads peculiar to crossties, and non-adaptability ofsome materials to spikes or screws for fastening rails to crossties.

[0013] Accordingly, a need exists for a substitute for the conventionalwooden crosstie that will successfully solve the problems of highoriginal cost, frequent replacement, and polluting disposal.

BRIEF SUMMARY OF THE INVENTION

[0014] The present invention consists of a new form of railroadcrosstie, made primarily of used vehicle tire treads, bound together andstiffened by the addition of a stiffening element. The present inventionis easy to manufacture, very low in cost, and will greatly outlastwooden crossties, thus significantly increasing the economic efficiencyof the railroad industry. The present invention is environmentallyneutral, and uses up an abundant consumer and business byproduct, namelyused tires, which currently present serious environmental problems dueto the difficulty of disposing of them. The present invention replaceslumber crossties, which consume scarce lumber resources and whichpresent environmental problems both during their useful lifespan and atdisposal.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0015]FIG. 1 is a side elevation of the railroad crosstie of the presentinvention.

[0016]FIG. 2 is a sectional end view of the railroad crosstie of thepresent invention.

[0017]FIG. 3 is a top view of the railroad crosstie of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0018]FIG. 1 is a side elevation of the railroad crosstie of the presentinvention, which preferentially includes a plurality of elongated,substantially planar elastomeric members 10. The members 10 areassembled together in a stack such that the members 10 are generallyaligned with each other. The members 10 may each be of the full lengthof the crosstie, or may be less than the full length, in which case themembers 10 are butted end-to-end as shown. The ends 18 of such shorterlengths of elastomeric members 10 meet within the body of the crosstie.

[0019] The drawing shows the binding units 14 being comprised of strapsof a flexible material. The binding units 14 keep the members aligned,and prevent them from shifting under the weight and movement of a trainon the rails.

[0020] In the preferred embodiment, the binding units 14 also providecompression of the members 10. The passage of a train typically causes atemporary depression a section of crossties, as can be observed when aloaded train passes over a given section of track. Following thisdepression, there is a lifting moment as the rail assembly returns toits original configuration. This cycle of depression and lifting becomesgreater as the speed and weight of the train increase. Beyond certainthresholds of train speed and weight, a sufficient compression of themembers 10 by the binding apparatus 14 is required to prevent unduemovement of the surface of the crosstie when exposed to these cyclicaldepressing and lifting moments.

[0021] This figure shows a stiffening element 17 comprising a piece ofsteel angle iron placed along an upper corner of the crosstie. Thestiffening element 17 is enclosed within the binding units 14, whichserve to keep the stiffening element 17 bound against the elastomericmembers 10.

[0022]FIG. 2 shows an end-view cross-section of the crosstie of thepresent invention. The drawing shows two stiffening elements 17,comprising pieces of angle iron, held against the elastomeric members 10by means of the binding units 14. Other embodiments of the presentinvention utilize one or more stiffening elements placed at differentlocations along the outside of, or embedded within, the body ofelastomeric members. The stiffening elements may be either metal orother materials.

[0023]FIG. 3 shows a top view of the crosstie of the present invention.The stiffening elements 17 overlap the top of the uppermost elastomericelement 10, and are bound to the body of the crosstie by the bindingunits 14. This figure shows the binding elements 14 arranged in astaggered formation along the length of the crosstie. In the preferredembodiment, the binding units 14 cross approximately three-fourths ofthe width of the top of the crosstie and then penetrate the stack ofelastomeric members 10.

[0024] The drawings illustrate one of many possible embodiments of thebinding units 14. Other embodiments of the present invention utilizerigid binding units, as for example, welded metal units; and otherembodiments may also require the use of binding methods other thanwelding, such as screws, bolts, crimping, adhesives, thermal processes,or other methods.

[0025] The forgoing descriptions relate to embodiments of the presentinvention which include the preferred embodiment, and are not meant tolimit the scope of the invention. From the forgoing descriptions, manyvariations will be apparent those skilled in the art that would beencompassed by the spirit and scope of the present invention.Accordingly, the scope of the invention is to be limited only by theclaims thereof and their legal equivalents.

[0026] The railroad crosstie of the present invention includes aplurality of elongated, substantially planar, elastomeric members. Themembers are assembled together in a stack such that the members aregenerally aligned with each other. In the preferred embodiment, themembers are made of tire treads cut from vehicle tires, included but notlimited to car, truck, and trailer tires. Elastomeric members formedspecifically for this invention, and not made from tire treads, wouldalso be within the scope of the present invention. Additionally, thestack of elastomeric members could be replaced by a single elastomericmember of a thickness, density, and strength sufficient for the intendeduse.

[0027] Some of the tire treads available for use in the presentinvention are of a length equal to or greater than that of a standardcrosstie, whereas other treads may be shorter than the full length of acrosstie. As the drawings show, the shorter lengths of tread can be laidend-to-end within the stack of treads.

[0028] A means of binding is provided for holding the stack of memberstogether. The binding means can include flexible or rigid fasteners,such as straps or metal rods, and may utilize means of joining such asbolts, screws, rivets, crimping, or welding. Additionally, theelastomeric members may be directly attached to each other through theuse of adhesives or chemical or thermal processes.

[0029] One or more stiffening elements are incorporated within, orplaced along the outside of, the stack of elastomeric members. Thebinding units can be attached to the stiffening element(s) to facilitatethe assembly of the crosstie, or to increase the overall rigidity of thecrosstie. In various embodiments of the present invention, the bindingmeans and the stiffening element(s) may be separate, or may be attachedto each other, or may be incorporated together.

[0030] One purpose of the stiffening element(s) is to resist the flexionor distortion of the crosstie that may occur during the process ofinstalling the crosstie. In current practice, the replacement of wornand rotted wooden crossties utilizes machinery that inserts the newcrosstie under the rails by picking up the crosstie at one end andsliding it under the rails. Thus the crosstie must be stiff enough to behandled in this fashion.

[0031] Another purpose of the stiffening element(s) is to preventflexion of the crosstie when, due to erosion or movement of the stoneballast supporting the crosstie, the crosstie is supported in the middlebut not well supported at one or both ends. In this situation the weightof passing trains tends to bend the crosstie down at the ends. Thisbending could, over time, cause misalignment of the rails. Therefore thestiffening element(s) help maintain the correct alignment of the rails.

[0032] Rail plates can be attached to the crosstie of the presentinvention by inserting spikes or screws through the plates and into theelastomeric members.

[0033] It is an additional objective of the present invention to providesuch a railroad crosstie that, by virtue of the inherent flexibility ofthe primary material from which it is made, it is particularly resistantto cracking at specific locations along its upper and lower surfaces dueto bending-induced cyclic tensile stresses peculiar to railroad ties.

[0034] It is an additional objective of the present invention to providea crosstie that will have a long service life, far in excess of that ofconventional wooden crossties.

[0035] It is an additional objective of the present invention to providea crosstie that will be inert an friendly to the environment, creatingan end-use product out of vehicle tires that are currently going intolandfills, are shipped offshore, or are accumulating in dumps andcreating environmental problems.

[0036] Because the present invention is assembled preferentially fromtire treads, recyclable materials will be used instead of lumber, whichis expensive and in short supply.

We claim:
 1. A railroad crosstie comprising: a. a plurality ofelongated, substantially planar, elastomeric members assembled togetherin a stack such that the members are generally aligned with each other;b. a means of binding the elastomeric members together and keeping themaligned with each other; c. one or more stiffening elements placedlongitudinally within, or along the outside of, the stack of elastomericmembers, composed of a substantially rigid material, sufficiently rigidto prevent excessive flexion and deformation of the crosstie.